Hey Scar the best route to go for learning and fun is look for the Williams system 11 machines from 1986-90. They have a wide range of titles and prices but there is tons of parts available and knowledge banks out there that it makes working on them fun. You can do a lot with them on a modest budget including upgrading to LED lights and Titan competition rings. Playfield condition is always your first place to decide on buying. Look for ones that don't have large patches of wear in the playfield. Machines can always be fixed, circuit board and parts replaced but replacing the playfield is a very challenging and expensive endeavor.

DITTO High Speed Jump on it!